1/*
2 * Copyright (C) 2012 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef RegExpCachedResult_h
27#define RegExpCachedResult_h
28
29#include "RegExpObject.h"
30
31namespace JSC {
32
33    class JSString;
34    class RegExpMatchesArray;
35
36    // RegExpCachedResult is used to track the cached results of the last
37    // match, stores on the RegExp constructor (e.g. $&, $_, $1, $2 ...).
38    // These values will be lazily generated on demand, so the cached result
39    // may be in a lazy or reified state. A lazy state is indicated by a
40    // value of m_result indicating a successful match, and a reified state
41    // is indicated by setting m_result to MatchResult::failed().
42    // Following a successful match, m_result, m_lastInput and m_lastRegExp
43    // can be used to reify the results from the match, following reification
44    // m_reifiedResult and m_reifiedInput hold the cached results.
45    class RegExpCachedResult {
46    public:
47        RegExpCachedResult(VM& vm, JSObject* owner, RegExp* emptyRegExp)
48            : m_result(0, 0)
49        {
50            m_lastInput.set(vm, owner, jsEmptyString(&vm));
51            m_lastRegExp.set(vm, owner, emptyRegExp);
52        }
53
54        ALWAYS_INLINE void record(VM& vm, JSObject* owner, RegExp* regExp, JSString* input, MatchResult result)
55        {
56            m_lastRegExp.set(vm, owner, regExp);
57            m_lastInput.set(vm, owner, input);
58            m_result = result;
59        }
60
61        RegExpMatchesArray* lastResult(ExecState*, JSObject* owner);
62        void setInput(ExecState*, JSObject* owner, JSString*);
63
64        JSString* input()
65        {
66            // If m_result showas a match then we're in a lazy state, so m_lastInput
67            // is the most recent value of the input property. If not then we have
68            // reified, in which case m_reifiedInput will contain the correct value.
69            return m_result ? m_lastInput.get() : m_reifiedInput.get();
70        }
71
72        void visitChildren(SlotVisitor&);
73
74    private:
75        MatchResult m_result;
76        WriteBarrier<JSString> m_lastInput;
77        WriteBarrier<RegExp> m_lastRegExp;
78        WriteBarrier<RegExpMatchesArray> m_reifiedResult;
79        WriteBarrier<JSString> m_reifiedInput;
80    };
81
82} // namespace JSC
83
84#endif // RegExpCachedResult_h
85